Laser Applications in Orthodontics

A laser is a collimated single wavelength of light which delivers a concentrated source of energy. Soon after different types of lasers were invented, investigators began to examine the effects of different wavelengths of laser energy on oral tissues, routine dental procedures and experimental applications. Orthodontists, along with other specialist in different fields of dentistry, can now benefit from several different advantages that lasers provide during the treatment process, from the beginning of the treatment, when separators are placed, to the time of resin residues removal from the tooth surface at the end of orthodontic treatment. This article outlines some of the most common usages of laser beam in orthodontics and also provides a comparison between laser and other conventional method that were the standard of care prior to the advent of laser in this field

Learning with Exposure Constraints in Recommendation Systems

Recommendation systems are dynamic economic systems that balance the needs of multiple stakeholders. A recent line of work studies incentives from the content providers' point of view. Content providers, e.g., vloggers and bloggers, contribute fresh content and rely on user engagement to create revenue and finance their operations. In this work, we propose a contextual multi-armed bandit setting to model the dependency of content providers on exposure. In our model, the system receives a user context in every round and has to select one of the arms. Every arm is a content provider who must receive a minimum number of pulls every fixed time period (e.g., a month) to remain viable in later rounds; otherwise, the arm departs and is no longer available. The system aims to maximize the users' (content consumers) welfare. To that end, it should learn which arms are vital and ensure they remain viable by subsidizing arm pulls if needed. We develop algorithms with sub-linear regret, as well as a lower bound that demonstrates that our algorithms are optimal up to logarithmic factors.Comment: Published in The Web Conference 2023 (WWW 23

Design, Simulation and Implementation of a High Step-up Z-source DC-DC Converter with Flyback and Voltage Multiplier

Nowadays, because of pollution problems of the fossil fuels and their unpleasant effects on the earth planet and people life, renewable energy sources such az photovoltaic (PV) cells and fuel cells are considered to produce electrical energy. These sources directly convert solar energy and chemical energy to electrical energy, respectively. Since the output voltage of PV cells is low, a high step-up dc-dc converter is needed to increase this low voltage to meet inverter input required voltage. In this thesis, a novel high step-up dc-dc converter (which is the derivation of z-source converter) is introduced. This converter has a higher voltage gain in comparison to the conventional converters. This advantage makes this converter a suitable choice for high step-up applications, such as boosting the low output voltage of solar panels. Also, by choosing appropriate turns ratio of the coupled inductors, the proposed converter can be used for a wide range of voltage gain. First, the z-source converter is analyzed and the conventional high step-up converters are discussed. Then, the new high step up converter is proposed and analyzed. The converter is simulated and the results are compared to the theoretical results. The proposed converter is then experimentally tested. The experiment results verify the theoretical and simulation results. Finally, the proposed converter is compared to the conventional ones and it’s advantages such as having higher voltage gain are confirmed

VacA, CagA, IceA and OipA Genotype Status of Helicobacter pylori Isolated from Biopsy Samples from Iranian Dogs

Purpose: To investigate the state of vacA, cagA, oipA and iceA genotypes of H. pylori isolated from gastric biopsy samples of dogs.Methods: A total of 240 gastric biopsy samples were taken from 240 dogs using gastric endoscope. All the samples were cultured and H. pylori-positive samples were analyzed for the presence of various genotypes using polymerase chain reaction (PCR).Results: Thirteen out of 240 (5.41 %) samples were positive for H. pylori with a higher prevalence of the bacterium in dogs with gastric ulcer (6.36 %). The most commonly detected genotypes were vacA s1a (53.84 %), cagA (46.15 %) and vacA m2 (38.46 %). Total prevalence of iceA1, iceA2 and oipA genotypes were 23.07, 10.8 and 10.81 %, respectively. M2s1a (30.76 %), m1am2 (30.76 %) and m1as1a (23.07 %) had the highest prevalence among other detected combined genotypes. Twenty-two different genotypic combinations were detected with higher prevalence of s1a/cagA+/iceA1/oipA- (23.07 %), m2/cagA+/iceA1/oipA- (23.07 %), and s1b/cagA+/iceA1/oipA- (15.38 %) genotypes.Conclusion: The presence of similar genotypes in H. pylori strains of gastric biopsy samples of dogs and those of human clinical specimens suggest that dogs may be the source of the bacterium. Proper handwashing and avoidance contact with feces and saliva of dogs are recommended to prevent transmission of H. pylori.Keywords: Helicobacter pylori, Genotype, Genotyping, Gastric biopsy, Iranian dog

Comparison of Toxoplasmosis prevalence in individuals with and without cat contact in Isfahan using indirect Immunofluorescent

زمینه و هدف: توکسوپلاسما گوندی ای عامل توکسوپلاسموز یک انگل کوکسیدیایی داخل سلولی اجباری است که تقریباً تمام گونه های حیوانی خونگرم و انسان را مبتلا می کند. گربه ها به عنوان میزبان نهایی یکی از منابع عمده و برجسته ی انتشار عفونت و آلودگی انسان در طبیعت تلقی می گردند. مطالعه حاضر با هدف تعیین میزان آلودگی به توکسوپلاسما در صاحبان گربه های خانگی و مقایسه آن با میزان آلودگی در افرادی که سابقه نگهداری از این حیوان را نداشته اند، انجام شد. روش بررسی: در این مطالعه توصیفی تحلیلی 120 نفر (60 نفر بدون تماس با گربه و 60 نفر دارای گربه خانگی) از مراجعین درمانگاه دام کوچک دانشکده دامپزشکی دانشگاه آزاد اسلامی واحد شهرکرد واقع در اصفهان در فاصله زمانی آغاز سال 1384 تا انتهای فصل پاییز همان سال به روش نمونه گیری تصادفی ساده انتخاب گردیدند. نمونه های سرمی تهیه شده از آنان از نظر وجود آنتی بادی های ضد توکسوپلاسمایی با استفاده از روش الایزا و ایمنوفلورسانس غیرمستقیم مورد بررسی قرار گرفت و داده ها با استفاده از آزمون های آماری کای دو و تست دقیق فیشر تجزیه و تحلیل گردید. یافته ها: در مجموع تعداد 35 نمونه (13 نمونه از افراد در تماس و 22 نمونه از افراد بدون تماس با گربه خانگی) دارای IgG ضد توکسوپلاسما بودند. هیچکدام از نمونه ها پادتن IgM ضد انگل را نشان ندادند. همچنین میزان آلودگی در مردها 17/34 درصد و در زنها 51/19 درصد برآورد گردید. ارتباط آماری معنی داری بین میزان آلودگی به توکسوپلاسما و سابقه نگهداری گربه های خانگی و نیز بین جنسیت و سن با میزان آلودگی وجود نداشت (05/0P>). نیتجه‌گیری: با توجه به نتایج این مطالعه بخش عمده ای از صاحبان گربه های خانگی تاکنون با انگل مواجهه نداشتند و نسبت به آن حساس می باشند. لذا آموزش صاحبان گربه‌های خانگی و ارتقاء سطح آگاهی آنها در مورد راههای انتقال عفونت و بررسی آلودگی گربه‌های خانگی و جلوگیری از آلودگی آنها توصیه می گردد